It is well known that superconductive materials, such as powders and ceramics therefrom, have received greatly increased attention with the discover of a variety of relatively high temperature (liquid nitrogen temperature) superconductor materials. For example, YBa.sub.2 Cu.sub.3 O.sub.7-x is a superconductive ceramic material that is also known as 123 compound or YBC material. The property of this superconductive material, as well as the other superconductors, tends to be process dependent. The transition temperature (metal/semiconductor to superconductor transition) and the room temperature resistivity are very sensitive to the homogeneity and oxygen content of the calcined material. The conventional mixed oxides process produces coarser agglomerate which needs to be calcined for a long time at near melting temperature to achieve a high degree of homogeneity. Stoichiometry on a macro- and microscale is of critical importance, particularly with respect to stoichiometry-driven crystal defects. The result is the formation of relatively large size particles. Bulk or thick films made of large particle size powder are very porous and have rough surfaces which are not suitable for radio frequency (RF) applications. Other chemical processes such as amorphous citrate processes and freeze-drying processes are difficult to adapt to mass production at good stoichiometry, which is a requirement for commercialization of these materials.
Good superconductive materials seem to require a certain grain structure. Identified desirable qualities include little or no microcracking at grain boundaries; low resistivity grain boundaries, at least in the direction of current flow; and classical grain-boundary pinning phenomena.
Examples of previous processes are described in many articles that have published in the last few years. However, it would be desirable if a new process were discovered that permitted simple equipment to be used, allowed mass production of stoichiometric fine powders, and which generated no harmful chemical wastes as do some of the known procedures.